Sandbox should always use go
On jujucharms, bundle deployment wasn't working because we were using the python sandbox (because jujucharms still uses pyjuju). Thank you to Francesco for noticing, diagnosing, and offering a fix. This is his fix with a quick test.
https://code.launchpad.net/~gary/charms/precise/juju-gui/legacyJujucharms/+merge/195293
(do not edit description out of merge proposal)

*** Submitted:
Sandbox should always use go
On jujucharms, bundle deployment wasn't working because we were using the python
sandbox (because jujucharms still uses pyjuju). Thank you to Francesco for
noticing, diagnosing, and offering a fix. This is his fix with a quick test.
R=bac
CC=
https://codereview.appspot.com/26430044